下列程序输出的结果是( )。#include＜stdio.h＞sub1(char a，char b) {char c：c=a：a=b：b=c; }sub2(char*a,char b) {char c：c=*a；”a=b；b=c；}sub3(char*a，char*b) {char c；c=*a；”a=*b；*b=c；}void main() { char a,b;a=’A’；b=’B’:sub1(a，b)；putchar(a)：putchar(b)：a=’A’；b=’B’; sub2(&a，b)；putchar(a)；putchar(b)；a=’A’；b=’B’; sub3(&a，&b)；putchar(a)；putchar(b)；putchar(’\n’)；}

A．ABABAB

B．ABBBBA

C．ABBABA

D．ABABBA